WebUI NTP: voice search, prevent text causing jitter for narrow widths

Bug: 1116953
Change-Id: I7a454072c190da5f1363f7c98027c81c5b19aa0e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2459168
Commit-Queue: Esmael Elmoslimany <aee@chromium.org>
Commit-Queue: Tibor Goldschwendt <tiborg@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Auto-Submit: Esmael Elmoslimany <aee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#816371}

chrome/browser/resources/new_tab_page/voice_search_overlay.html

@@ -68,6 +68,8 @@
   *[text='waiting'],
   *[text='speak'] {
     opacity: 0;
+    /* Hiding overflow to prevent jitter when the content area is narrow. */
+    overflow-x: hidden;
     padding-inline-start: 50px;
   }